For details check here for demomen and here for soldiers.
A lot of great additions this update, perhaps the best yet. Eyelander+charging targe is great fun and completely changes how one normally plays demoman. Instead of aoe artillery you get a melee fighter with some range capability. The Soldier's Equalizer somewhat mirrors the demoman combo, he gains much more melee deadliness, but it's not something that you can risk using often. The pick axe is a definite upgrade. The charging targe and eyelander either go together or they don't, they might as well be one item. Without the charge you aren't going to get enough melee kills to make the eyelander worthwhile, and without the eyelander you aren't going to last long with just a targe and bottle. I haven't obtained the new rocket launcher yet, but I suspect it is an upgrade to the ordinary main slot in much the same way as the ambassador was. In the hands of a skilled player it will be much more effective. The buff banner seems to offer the same choice as the heavy's sandwhich, additional utility at the cost of a backup plan.
I also found the achievements to be more difficult to obtain just because there appears to be so many that require you to already have the weapons to complete, though they did lower the requirement greatly.